This invention relates to an occlusion device for the closure of physical apertures, such as vascular or septal apertures. More specifically, this invention relates to an occlusion device for the heart that can be retrieved, reloaded, and redeployed in situ.
The heart is generally comprised of four chambers: the left and right atrium and the left and right ventricle. Separating the left and right sides of the heart are two walls, or septa. The wall between the two atria is the interatrial septum, and the wall between the two ventricles is the interventricular septum. There are several defects which can affect the septa of both children and adults, including patent ductus arteriosus, patent foramen ovale, atrial septal defects (ASDs), and ventricular septal defects (VSDs). Although the causes and physical characteristics of these defects vary by type, each of these defects is generally an aperture, flap, or hole in the septum which allows blood to shunt between chambers in the heart where there is no blood flow in a normal, healthy heart. This abnormal shunt can cause a variety of health problems.
Normally, permanently repairing certain cardiac defects in adults and children requires open heart surgery, which is a risky, painful, and expensive procedure. Surgery for closure of a heart defect is major heart surgery, which requires the patient to undergo general anesthesia and opening of the chest cavity. The patient must spend several days in the hospital and takes several weeks to be able to return to normal levels of activity.
To avoid the risks and discomfort associated with open heart surgery, modern occlusion devices have been developed that are small, implantable, and capable of being delivered to the heart through a catheter. Rather than surgery, a catheter inserted into a major blood vessel allows an occlusion device to be deployed by moving the device through the catheter to the treatment site within the body. This procedure is performed in a cardiac cathlab and avoids the risks, pain, and long recovery associated with open heart surgery.
There are currently several types of occlusion devices capable of being inserted via a catheter including button devices, collapsible umbrella-like structures, and plug-like devices. These modern occlusion devices can repair a wide range of cardiac defects, including patent foramen ovale, patent ductus arteriosus, atrial septal defects, ventricular septal defects, and may occlude other cardiac and non-cardiac apertures. One form of occlusion device generally has a left side, a right side, and a center section. Once the occluder is deployed, the left side sits in the left side of the patient's heart and the right side sits in the right side of the patient's heart. The occluder's center section extends through the center of the defect. The left and right sides occlude the aperture on the respective sides of the patient's septum.
To deploy the occlusion device, a physician loads the device into a catheter, advances the device via catheter to the treatment site, and deploys the device at the treatment site. Loading the device into the catheter must be done by hand, and requires a high degree of manual dexterity and takes time. Once the device is loaded, it is maneuvered through the catheter to the treatment site within the body. In the event the device is not deployed properly or effectively, it must be retrieved and the procedure must be performed again. Some of these devices are retrievable via catheter, but many require open heart surgery to be retrieved. Once retrieved, many types of occlusion devices cannot be redeployed. In such instances, a new occlusion device must be used, increasing the cost of the procedure.
Even if the device can be retrieved using a catheter, retrieval may require insertion of a larger diameter catheter. A larger diameter catheter may be needed because the device may not readily resume the compact shape it had before deployment. Once retrieved, the device may be compromised from the stress of withdrawing it back into the catheter, even if a larger diameter catheter has been used. As such, it may not be possible to reuse the retrieved occlusion device.
In addition, devices retrieved via catheter do not necessarily reload for redeployment when they are retrieved. Even if the device can be re-used, it must be completely removed from the catheter to be properly reloaded. Thus, even if the device is retrievable, the device must be pulled back through the catheter, removed, and reloaded. Once again, just as with the loading procedure, reloading is time consuming and requires high manual dexterity. This adds extra time to the procedure, and creates wear and tear on the device. Often, the retrieved device cannot be reused because it has been damaged by the retrieval process. If the device cannot be reused, a new device must be used, adding to the cost of the procedure.
Thus, there is a need in the art for an occlusion device that is easier to load into a catheter and can be retrieved, reloaded, and redeployed in situ.